Small-scale transient phenomena in the quiet Sun are believed to play an
important role in coronal heating and solar wind generation. One of them named
as "X-ray jet" is the subject of our study. We indent to investigate the
dynamics, evolution and physical properties of this phenomenon. We combine
spatially and temporally multi-instrument observations obtained simultaneously
with the SUMER spectrometer onboard SoHO, EIS and XRT onboard Hinode, and
EUVI/SECCHI onboard the Ahead and Behind STEREO spacecrafts. We derive plasma
parameters such as temperatures and densities as well as dynamics by using
spectral lines formed in the temperature range from 10 000 K to 12 MK. We also
use image difference technique to investigate the evolution of the complex
structure of the studied phenomenon. With the available unique combination of
data we were able to establish that the formation of a jet-like event is
triggered by not one but several energy depositions which are most probably
originating from magnetic reconnection. Each energy deposition is followed by
the expulsion of pre-existing or new reconnected loops and/or collimated flow
along open magnetic field lines. We derived in great detail the dynamic process
of X-ray jet formation and evolution. We also found for the first time
spectroscopically in the quiet Sun a temperature of 12~MK and density of 4
10^10~cm^-3 in a reconnection site. We raise an issue concerning an uncertainty
in using the SUMER Mg X 624.9 A line for coronal diagnostics. We clearly
identified two types of up-flow: one collimated up-flow along open magnetic
field lines and a plasma cloud formed from the expelled BP loops. We also
report a cooler down-flow along closed magnetic field lines. A comparison is
made with a model developed by Moreno-Insertis \etal\ (2008).Comment: 15 pages, 15 figure
